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7K views 35 replies 11 participants last post by  cadillacmike68 
#1 ·
I know that most of you think that Lower crankcase seals are not necassary to be repaired and have questioned the fact that I recommend them being done due to oil pressure issues...I visited a shop this week on a field tech assist and had all the service advisors and techs in a meeting. The service advisors had points like many of yours about this not being a critical repair..I advised them for a number of years of this problem can cause serious and sometimes even catastophic damage to lower and upper end of engine..so I figured I would post some information and you guys can make your own calls about your own vehicles..
with this I will show you pictures of how this works for those of you who do not know the inner workings of your N*....
Figure 1...look at the frt of this lower crankcase already removed from the engine...see the 2 large holes in frt that is where the oil pump feed and release is...

figure 2....at the top is where the pickup is that follows thru to the right into the oil pump which releases the pressure below that to lower galley to feed through the oil pump...from there back into lower crankcase freeding all 5 main bearings..

figure 3 ...notice the hole on the far left...this feeds the top end....

figure 4.... is the oil manifold notice the inpregnated gaskets...and you can see how this seals the try to keep the oil contained....now notice the outer secondary seal which keeps it leaking externally...If you begin to leak externally are you not leaking internally???thus losing oil pressure to top and bottom of engine causing saddle and bearing damage....

I dont want to scare you guys, but this is a major needed repair...I dont make money on you doing them, just trying to shed some truth..Worst case scenerio if you do not do them for a few years and they are dripping all over the place you will need lifters, cams, crankshaft ect....Minor seeping is not a problem and even a lot more, but if it is flowing back onto the trans pan they need to be done...Not right away but soon...use your judgement..
 

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#3 ·
Good info and great pics. Thanks
 
#4 ·
Just curious what the flat rate time for that is? I'd like to get mine repaired but my only option is going through my after market warranty. I know how much it sucks to deal with them since I do it on a daily basis, but I don't have a few grand sitting around ready to fix this problem. My only solution is to use the warranty on it, but they don't cover the full labor at the dealer as I'm sure you know. If I could reasonably afford the difference in cost on the labor, than I'd do it in a heartbeat. I've got other cars I can use while it in. Plus, it'd be nice to finally get the missing oil pan bolt replaced, and have the front seal looked at. Have you seen any N*'s with a dry front crank seal? Mine seems to be squealing a little on cold start up and quites down once warmed up. A buddy of mine at work has a dried out front crank seal on the Vortec motor in his Yukon, and it's squealing on him to. Sounds like a birds living int he engine bay...haha. Anyway, just curious if you've seen this before.
 
#5 ·
Flat rate for the half case reseal is 10.2 hrs not counting engine removal, which I believe is 2.5 or something like that.
 
#6 ·
I dont want to scare you guys, but this is a major needed repair...I dont make money on you doing them, just trying to shed some truth..Worst case scenerio if you do not do them for a few years and they are dripping all over the place you will need lifters, cams, crankshaft ect....Minor seeping is not a problem and even a lot more, but if it is flowing back onto the trans pan they need to be done...Not right away but soon...use your judgement..
I'm not saying your wrong, but I havn't heard of or read about "any" oil pressure related problems, ever, that have to do with the case half seal on this or ***************, or in my experience as a tech. If there's a leak in the pressurized oil circuit anywhere, wouldn't it register on the DIC via the oil pressure switch? Even if it's internal? I know when you have worn bearings on any engine with a mechanical oil pressure gauge, it registers on that. And that is considered an internal leak.
 
#7 · (Edited)
the pressure is guaged at oil filter housing not at top end..it is the first stop after oil pump and before entering crank area..so at that point there will not register on the DIC or through the PCM..also if there is an external leak what about the internal? that pressure does go down and by testing at the head is the only way to be positive that you are getting the correct pressure.So what you have to look for is a lower oil manifold/crankcase seal leak....I have experienced ton of documented cases through the years mostly in severe weather change areas that have in fact ruined the life of engine and degragated the bearings..


AND DANBUC....no need to remove engine to do this repair, the national average at customer pay is 19.0 hrs at a dealership...15.7 for 93-99..18.4 99-up
 
#11 ·
I advised them for a number of years of this problem can cause serious and sometimes even catastophic damage to lower and upper end of engine..
How come you didn't mention this on January 10th in this post?? See post 10


http://www.cadillacforums.com/forum...hnical-discussion/95473-oil-level-sensor.html

If you have ever had one apart you would see that the oil manifold keeps in alot, standard for that is 10 quarts and after doing over 200 in just 2006 (they keep track of that crap at dealerships due to auditing) never had one problem last year or since 1993.






Any of those 200 case half seal jobs have "catastrophic damage" ??
 
#12 ·
New bearings in alot of them, along with new pumps, 2 new crankshafts, new lifters..depending what you would call catastophic..as to refer to that post it is out of context...no problems in filling the oil at 10 quarts.....
Look I am just trying to shed light on the truth what you want to do with your car is your own business and I personally dont care if you want to drive around with a leaking engine, just dont park in my driveway or complain when you need bearings and other major work done because you thought it was not a pertinant repair...This site is filled with people that love and cherish their cadillacs. Are we more concerned with the appearence of it or the feeling of comfort.how is that all going to be when it is sitting in the front driveway and does not run??? Or a 2k repair job just turned into 4k or new engine is that justified??? .personally I love the fact that it is a reliable vehicle and I want to keep it that way. So by doing what needs to be done when it is time is a critical thing to me.
I have said time and time again to get them done when you can not to let them get severe..they may seep for a few years before they become a problem. and with any problem would you not want to get them fixed or are you just going to question that to???say thats opinion???the facts are there I have explained it good enough do as you will..........
 
#14 · (Edited)
New bearings in alot of them, along with new pumps, 2 new crankshafts, new lifters..depending what you would call catastophic..
Not me, it's what you called catastrofic.


I advised them for a number of years of this problem can cause serious and sometimes even catastophic damage to lower and upper end of engine..


Look I am just trying to shed light on the truth what you want to do with your car is your own business and I personally dont care if you want to drive around with a leaking engine, just dont park in my driveway or complain when you need bearings and other major work done because you thought it was not a pertinant repair...


My engine is bone dry. I doubt I'll ever need "major work", I maintain my vehicle. However if my casehalf ever did need to be replaced, I'm more then capable as a factory trained & ASE certified Mercedes Benz technician.

I don't buy your "story" about this. If this was such a wide spread problem, we all would have heard reports on here like we do about headgaskets. I'm not going to go back and forth with you on this, there's really no way to prove your theory that the leaking case half seal causes a loss of oil pressure to any part of the engine. In a case like that, your conclusion IS an opinion. Just because you've taken apart a N* with a leaking case half and it had bearing damage doesn't mean that's what caused it. You said above "new bearings in alot of them, along with new pumps". Would that be oil pumps?? Why were they replaced? Low oil pressure?
 
#15 ·
Either the engine has to come out, or the transmission has to come out.
You cannot (or at least should not) service this component with the engine and transmission connected together because of the exhaust crossover.

GM warranty time for lower crankcase reseal is 14.7 hours.
Alldata shows a COD pay time of 3.0 plus engine removal which pays about 15 hours. (based on a 2000 Deville)

I can see how a lower crankcase failure could be an indication of an oil manifold seal failure but I wouldn't necessarily make the assumption that a lower crankcase leak is directly related to such a failure as a rule.

If I understand the basic principles of hydraulics, the pressure is the same everywhere in the system, that means if a leak springs out somewhere, systemic pressure will be lowered unless there is a restriction between the sending unit and the component that is not being oiled, in which case it won't matter anyway because there is a restriction.

I would agree with your general point Cad Tech, and I am not trying to say that you are mistaken or insult you in any way. Your advice is sound to a degree. I would agree that a lower crankcase seal could indicate a larger internal oiling problem, but I don't really think the two are automatically linked together.

My personal opinon on a lower crankcase reseal is that if the leak becomes severe enough that it leaves drips on the ground, it should be fixed. If it is just slight buildup on the outside of the crankcase then for what it costs to fix, just check the oil regularly.

Just expressing my 2/100ths of a dollar.
 
#22 ·
"Cad tech", you need to re-read what ewill3rd said, he doesn't agree with you on everything you said just as I don't. He agree's that an internal leak will lower pressure "everywhere", so the DIC would let you know. I know pressurized oil runs through the pan/case half, not disputing that.. As a tech of over 25 years, I don't have to take apart a N* to know how it works. You say "I havn't heard of there failures because GM doesn't release to limit after warranty claims?? What,... these failures only occur while in warranty?
Your not going to convince me so let it go. The only way to prove yout point is to document via video a N* with a leaking case half, with a oil prssure gauge plumbed to the top end "showing" low pressure. Then after resealing the case half, the same gauge showing good pressure. In any case, re-read the quotes from ewill3rd below.




I can see how a lower crankcase failure could be an indication of an oil manifold seal failure but I wouldn't necessarily make the assumption that a lower crankcase leak is directly related to such a failure as a rule.

If I understand the basic principles of hydraulics, the pressure is the same everywhere in the system, that means if a leak springs out somewhere, systemic pressure will be lowered unless there is a restriction between the sending unit and the component that is not being oiled, in which case it won't matter anyway because there is a restriction.

I would agree with your general point Cad Tech, and I am not trying to say that you are mistaken or insult you in any way. Your advice is sound to a degree. I would agree that a lower crankcase seal could indicate a larger internal oiling problem, but I don't really think the two are automatically linked together.
 
#16 ·
ewill3rd, I agree with you 100%. That's the point I was trying to make. The oil pressure circuit is "one circuit". If there was an internal leak anywhere, it would be indicated via the oil pressure switch. Unless as you say there was a restiction to the pressure switch.
 
#18 ·
I'm actually semi-retired due to a disabilty. But when I still worked at a Benz dealer, they wouldn't let us do a major job like this. If however I did have to do my case half, I could do it in my garage at home, (500 sq ft) but I also work part time at a 5000 sq ft shop doing restoration work on Studebaker Avanti's and whatever else my boss wants to restore/collect. We just finished a 1963 Avanti for his son.
 
#19 ·
That's what I kinda figured. I can get away with a brake job and stuff but nothing crazy. My garage space is somewhat limited, plus I've already got my mother's '66 Triumph TR4-A up on jack stands in the middle of doing some minor work to it this winter. I wish I had somewhere to work on it, but oh well.
 
#21 ·
My engine is bone dry. I doubt I'll ever need "major work", I maintain my vehicle. However if my casehalf ever did need to be replaced, I'm more then capable as a factory trained & ASE certified Mercedes Benz technician.

I don't buy your "story" about this. If this was such a wide spread problem, we all would have heard reports on here like we do about headgaskets. I'm not going to go back and forth with you on this, there's really no way to prove your theory that the leaking case half seal causes a loss of oil pressure to any part of the engine. In a case like that, your conclusion IS an opinion. Just because you've taken apart a N* with a leaking case half and it had bearing damage doesn't mean that's what caused it. You said above "new bearings in alot of them, along with new pumps". Would that be oil pumps?? Why were they replaced? Low oil pressure?[/QUOTE]


Clark,
As you have so well put it you are a Mercedes Tech, this does not make you a cadillac tech because you own one or maybe worked on a few. I am not trying to pick a fight with you but you wanted to post questioning me. I work on these almost everyday, I am a GM master certified Tech, Cadillac craftsman league tech, Northstar factory trained in Lansing, Gm master certified Transmission specialist, and 4.6L, 4.0L, 3.8L, 4.9L 3100, 3400, specialist. I also do field research for GMTAC, and assist in development of TSB's on the N*, 4T-80E and 4.0L. also do field technical support for other dealerships across the country. I am also ASE certified (masters including L1,M1-3, and B2-5) member of NATEF..Now that we are on a level playing field..
You have not heard of reports because they are not released to limit after warrenty claims and you dont work for a GM dealership or a Heavyline tech for a GM dealer.
If you look at the pictures or ever had on apart enough to study the lubrication circuit. you would realize the simple truth.The cast aluminum oil pan is used as a structural member of the powertrain by connecting the pan and the transaxle case together with a bracket. The oil pan incorporates riveted internal oil baffle plates and seals to the lower crankcase with an O-ring gasket. The oil pan also provides mounting for an oil level sensor.

The oil sump pickup is fastened to the lower crankcase and oil manifold by a bolt and nut to one stud-headed main bearing bolt. A silicone seal, integral to the oil manifold, seals this joint on the suction side of the oil system. The engine oil pump is a gerotor design mounted to the lower crankcase behind the engine front cover by three mounting bolts. Drive for the gerotor elements is provided by the clamp load of the harmonic dampener and bolt. As the pump rotates, oil is drawn from the sump through the sump pickup to a channel cast into the lower crankcase. The oil is then directed to the pump inlet cavity on the lower crankcase front face. Oil compressed by the pump re-enters the lower crankcase distribution channel through the pump outlet cavity opposite the inlet. A portion of the pump output is diverted via an internal passage to the oil pump inlet to provide a pressure seal at the crankcase interface.

The oil pump outlet channel in the lower crankcase routes the oil to the oil filter/cooler circuit connections on the (front/left) side of the lower crankcase.

The cast aluminum oil filter adapter is fastened to the crankcase with two bolts. The inlet and return passages are sealed with O-rings. The adapter contains the oil pressure switch and two non-serviceable bypass valves. The oil filter bypass valve routes oil directly from the filter inlet to the filter outlet if the filter becomes plugged.

During normal operation oil flows from the adapter inlet through the oil filter. At this point oil flow is controlled by the oil cooler valve. This valve is closed when below its calibrated value and directs the oil filter output to the oil cooler located in the left hand radiator tank. Above the calibrated value the valve unseats and allows some of the oil to bypass the cooler and flow directly to the adapters return passage. Filtered and cooled oil re-enters the crankcase distribution channels and is simultaneously directed to the main bearings. Cross drilled passages in the crankshaft in turn provide oil for the connecting rod bearings and provide splash oiling for the cylinder walls. The lower crankcase distribution channel also connects with passages in the upper crankcase to provide oil to the overhead camshafts and valve lifters. This passage, beside the number one bearing, also provides oil for the three hydraulic chain tensioners as well as lubrication for the cam drive intermediate shaft ultimately lubricating the cam chains via oil splash.

I can tell you have maybe fewer then one of these apart so maybe just maybe you should not hold an opinion on this subject or post...So instead of trying to find faults and question me why not try and help others on what you know not speculation.

The problem exsists, What I am saying is that if you let it go for to long you can damage the engine...I am not saying that if it is seeping you should run out and do it either what I am trying to say there is a cause and effect to this problem.the cause no anerobic sealer applied in production, effect leaking oil internal and external.Cause leaking oil internally and externally, effect lower oil pressure top and bottem of engine. EOP at idle 5 PSI at 2k RPM 35PSI. Test it at head and EOP switch to get effective readings.
And as ewill3rd put it oil hitting the ground and I also say soaked trans pan...
 
#36 ·
....... The problem exists, What I am saying is that if you let it go for too long you can damage the engine...I am not saying that if it is seeping you should run out and do it either what I am trying to say there is a cause and effect to this problem.the cause no anerobic sealer applied in production, effect leaking oil internal and external.Cause leaking oil internally and externally, effect lower oil pressure top and bottem of engine. EOP at idle 5 PSI at 2k RPM 35PSI. Test it at head and EOP switch to get effective readings.
And as ewill3rd put it oil hitting the ground and I also say soaked trans pan...
Whoa Whoa whoa. Hold the presses:rant2:

Here we have a GM certified tech stating that the CAUSE of this is "...no anerobic sealer applied in production..."

Quick someone raise Frank Zappa up from the dead and send some lawyers, guns & money. :worship:

If this "cause and effect" is true, then GM should Repair EVERY leaking case half problem at NO CHARGE to EVERY Northstar owner EVERYWEHRE. They can start with mine :highfive:

Do I have a second on the class action suit?:stirpot:

Ir reminds me of the paint delamination problem that GM had in the late 80s to mid 90s but that problem only ruined the appearance of your car - and I had two cars with this problem a 92 Buick Lesabre and a 92 Chevy Corsica, the Corsisa was repainted at no charge because it was still "in warranty" but the Buick - they wouldn't repaint - "too far out of warranty" - right - so I showed them every repair bill that I had done elsewhere after that and brought over my my new Cadillac to show them when I bought it. :tisk:
 
#23 ·
Before you guys go on too far, I think maybe we should all stop and consider at this point what has been said and what more can come from arguing about the points that have been raised.

I think this might be one of those instances where all sides have been heard and it is up to people to make their own decisions.
None of us needs to be "more right" than the other.

I think Cad Tech raises some good points, and so does clark.

I would agree that the necessity for repair should be based on the severity of the leak and when it is all said and done it is always considered best to err on the side of caution. I would leave this discussion at that.
Anything further would just be pointless arguing.

I wouldn't mind hearing more opinon but I think it could be less personal.
:D
 
#26 ·
I appreciate your post. I feel like Columbus saying the world is round lol..
I have work with R&D engineers for years and turn down jobs in Warren and Lansing doing this full time. I feel my time and expertise is better use maintianing a working relationship with engines, trans , dealerships and tech.
Argueing with engineers over the real world and trying to walk the fine line with corperate is mind boggleing.the money saving measures between production and warrenty is also a factor, case and point head gasket issues.we knew that these exsist and were going to be a problem in 1992. till 2000 they did not want to install inserts from factory because of cost instead rediesign to save thier jobs.. 75% of Cadillacs do not stay under warrenty past 50k, the rest lie upon CCP and goodwill warrenty. so with the most failures occuring over 75000 miles why retool and install? This is what I get. Same issues with lower crankcase and oil manifold issues on installing anerobic sealer. Cost is to high so numbers is the key, the bottom line..
At any rate I am doomed to be ridiculed by the most of you who as with Human nature want to believe that that they dont need to be fixed and it is an easy out thus less money. which I can accept, if some told me that I did not need to shell out 2k on my car to fix it my car I would argue that untill I died....
 
#30 ·
FWIW, for many years gaskets of any kind were prohibited in British aircraft engines. The theory was that they may leak badly enough that you had to wear a rain coat to work on one but there was never going to be a catastropic leak from a blown out gasket. The British also developed some pretty exotic sealing goop mixtures. Anyone with experience working on British machines realizes that leaks never seemed to concern them very much. Limey cars and motorcycles always seemed to sit in the middle of a puddle of oil. Older American cars weren't much better. It took the Japanese to put across the idea that a car doesn't have to leak. An engine has to be spraying oil around like a lawn sprinkler before there is any worry about oil starvation of internal parts. The major concern with oil leaks is strictly esthetics from a practical viewpoint with some fringe effects involving fire.
 
#33 ·
In an effort to defuse the tension here, I would like to say that this is a very interesting and informative debate. I am learning things I did not know about the Northstar. I hope we can keep this as a professional non personal debate. I respect both of you guys and would hate to loose either of your expertise. :grouphug:
 
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